Was in a discussion today - can you use pond filters on a large FW aquarium, such as 200 gallons. The Bioforce 1000 for 1000 gal ponds can take a 600 gph pump. OASE's FiltoClear 800 is for 800 gal. ponds and can take a very high gph pump. One answer was that the aquarium requires more mechanical filtration, but does it over a pond? Trying to use T=9.2(v/f). Also would the flow be too quick past a 9 watt UV to make a difference (but if the filters recommend this gal. and pump, isn't the same amount of water going past the UV whether its from a 200 gal tank or an 800 gal pump?) Would too much internal pressure build in the filter, causing it to leak? What is the major diff. between a Bioforce and any other canister? They contain biomedia, pads, UV, etc. Thanks for your thoughts. I have no experience with pond filters, but it was an interesting topic (my biggest tank is 180 gal with a prof. Eheim filter) :P

going back to the quote thingy up there the reason the 200 gallon would kill more germs imo because it has more time to kill everything in the water. lets use cars for example. a corvette and a hybrid car. one will get you there faster and the other will use less gas. so depends on what you want more of. mechanical or whatever the uv does..

im just trying to use my common sense etc on this one because ive never had a uv. their so expensive

What krap said makes sense, but let me put it a bit differently. The UV filter kills based on exposure time. The slower you have your floor, the more that will be killed. The faster your flow, the more volume you filter. I think you just have to find a good balance of flow and go from there.